A driver transistor structure of an inkjet print head chip and the method for making the same. Having several body contacts distributed all over the source of an active region of a large area MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an equivalent RB from the MOSFET channel to the body contact is greatly diminished as the distance between them is reduced, thereby preventing the occurrence of a secondary breakdown. Since the body contact is installed inside the active region without defining in advance a body contact region and making the body contact in the field oxide layer outside the active region, about 20% of the driver transistor structure can be saved to lower the average manufacturing cost of each chip.